(1) Field of the Invention
The present invention relates to an integrated vane for use in wind or water, in which a vertical axis vane for use in wind or water power generation is improved in terms of lightweight, strength and performance, and a process for producing such an integrated vane for use in wind or water.
(2) Description of the Related Art
In recent years, the generation of electricity by wind or water power without using fossil fuels has been recognized once again worldwide from the viewpoints of global protection of the environment, energy security and economic growth.
As for the generation of electricity by wind power, a horizontal axis vane for use in wind, which has an axial shaft extending in the horizontal direction relatively to the ground and receives wind with one or more blades of a propeller type, has conventionally been employed. However recently, a vertical axis vane for use in wind, which has an axial shaft extending in the vertical direction relatively to the ground and a plurality of blades longer than they are wide extending in parallel with the axial shaft, for example, has appeared (referring to, for example, Japanese Patent Publication No. S56-42751).
The blade in the vertical axis vane for use in wind is fixed to the axial shaft with one or two support arm(s) extending in the horizontal direction. The support arm is formed in a thin flat plate-shape in order to minimize wind resistance upon rotation. The blade extending in the vertical direction is formed in a symmetrical or asymmetrical two-dimensional cross sectional shape of a blade. The blades, the support arms and the axial shaft constitute a vane (i.e., turbine) for use in wind.
However, since the conventional blade (main blade) as described above is, for example, joined to the support arm with a bolt through a flange, therefore the joining work is complicated, and it is difficult to secure the static or dynamic strength and fatigue strength for the joined portion between the blade and the support arm, resulting in a problem that the joined portion is easily damaged by high number of revolutions beyond allowance or operation for a long period of time. Further, since the joined portion has a large size and large weight, therefore the wind resistance during rotation increases and starting stability is deteriorated, resulting in that the efficiency (i.e., power coefficient) is deteriorated and the noise is increased. Furthermore, when the vane for use in wind described above is employed as a vane for use in water for use in water power generation, problems that the joined portion has poor strength as described above and the interior of the blade is flooded from a hole for joining the blade arise, therefore the common use of a vane for use in wind and for use in water has been substantially impossible.